1. Field of the Invention
The invention relates to a connector for the electrically conductive connection of a line without prior removal of its insulating sheaths, whose diameter is equal to or less than a given maximum value and which encloses a single or multiple wire metal conductor. The conductor has a diameter which is equal to or less than a given maximum value and which has a cross section that is at least approximately circular, and the connector has at least one clamping chamber which is open at its frontal faces and into which a length section of the line to be connected can be introduced. The longitudinal axis of the connector is defined by the longitudinal axis of such a length section of a line whose insulating sheath has a diameter corresponding to the given maximum value and is disposed in the clamping chamber when the connector is in the receiving position. The connector includes a connector body, at least one contact pressure member, each having at least one conical or wedge-shaped contacting element intended for penetration of the insulating sheath and entrance into the conductor. The tip of the contacting element or its cutting edge, respectively, lies in a first longitudinal center plane of the connector which also contains the longitudinal axis of the connector. The connector further includes a counterpressure member held at the connector body, with the contact pressure member or members being disposed on the one side and the counterpressure member or members being disposed on the other side of a second longitudinal center plane which passes perpendicularly through the first longitudinal center plane in the longitudinal axis of the connector.
The connector further comprises a tensioning member with which the contact members and the counterpressure members can be brought into a clamping position and can be fixed in such clamping position. Starting from the receiving position the distance between the contact member and the counterpressure member is greater than the maximum value of the outer diameter of the insulating sheath, while in the clamping position the distance between them is less than the minimum value of the diameter of the conductor.
2. Discussion of the Prior Art
In a known such connector, the connector body is composed of an approximately rectangular tubular section which is formed by bending over the edges of a punched sheet metal member and, at the point of intersection of its first longitudinal center plane with the transverse center plane of a threaded bore disposed in the center of its axial length, has an upper member formed by the one short side of the connector body.
In this prior art connector, a flat contact pressure member formed by a separate punched sheet metal member is disposed parallel to the second longitudinal center plane and is extended on one side and in one piece to form a connecting lug. The contact pressure member, at whose one flat side an actuation screw engages that is screwed into the threaded bore, is provided with a narrow rectangular sheet metal edge bent at a right angle on each side of the transverse center plane in such a manner that both sheet metal edges lie in mutually parallel planes which are also parallel to the transverse center plane and project in the direction of the other short side which forms the base member of the connector body. Both sheet metal edges are given a sawtooth configuration at their free edges.
Essentially in the same planes as these sheet metal edges, pairs of cams formed by embossing project inwardly from the base member of the connector body to serve as counterpressure members. The cams of each pair are disposed on different sides of the first longitudinal center plane and are provided with parallel ridges oriented toward the contact pressure member parallel to the longitudinal axis of the connector. The distance between these ridges corresponds approximately to the diameter of the conductor which is to be contacted by the connector.
In order to be able to easily introduce the conductor into the prior art connector under practice conditions, the inner width between the side members of the connector body must be selected to be considerably greater than the maximum outer diameter of the insulating sheath for which the connector is still to be usable. Special conductors whose insulating sheaths are smaller than this maximum value therefore take up an undefined position within the connector body. Thus, if the actuation screw is tightened, it is unlikely that a sawtooth of the contact pressure member will be seated precisely in the center of the conductor. It must rather be expected that the conductor will be gripped only by the sides of two adjacent sawteeth or will roll into this stable position where, at the occasion of the contacting process, remainders of the insulating sheath remain squeezed in between these edges and the conductor and may prevent reliable contacting even if a great force is exerted, or an oxide layer that may cover the conductor may not be reliably penetrate due to the tangential attack of the sides of the sawteeth.
Since the user of the connector is unable to discern the quality of the contact just made, he will generally tighten the actuating screw excessively, which results in mechanical damage and thus is in the danger of a break at the point of contact, particularly if the conductor is disposed in an unfavorable position within the connector body.
Even if a good contact should be made with the prior art connector, this contact may worsen after some time when the conductor material escapes due to cold flow and thus the contacting pressure is entirely or partially relinquished.